Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
58 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
What type of cells have no nucleus? |
Bacteria |
|
|
|
How does a light microscope function? |
Limited by properties of light so we cant see most of the organelles inside cells. |
|
|
|
How does a electron microscope function? |
Uses beams of electrons as the source of illumination. |
|
|
|
What is resolving power? |
The ability of an optical device to produce seperate images of close objects. |
|
|
|
Why are cells so small? |
Cells need surface area large enough for rapid efficient entry and exit of materials. |
|
|
|
What is surface -area-to-volume-ratio? |
The higher the ratio of the surface to the internal volume the fast the exchange of materials.
Cells have more surface area for exchange. |
|
|
|
The purpose of Microvilli: |
Used to absorb nutrients in the intesting. Small intestine 6-7 meters Large intestine 1.5 |
In the intestine. |
|
|
What is plasma membrane? |
Marks the boundary between outside and inside of a cell. |
|
|
|
Fuction of plasma membrane: |
Regulates passage in and out of a cell. |
|
|
|
What is the phospholidip bilayer? |
Two layers of the plasma membrane. Embedded with proteins. The polar heads or hydrophilic of phospholipids face into watery medium. The nonpolar tails or hydrophobic face each other. (Trying to stay away from the water). |
Can be seen in the fluid-mosaic model. The fluid-mosaic model is the structure of the plasma membrane. |
|
|
What type of cells can pass through the plasma membrane? |
Small and hydrophobic molecules can pass through the plasma membrane. |
|
|
|
What is a channel protein? |
1. Form tunnel for specific molecules. 2. Aquaporins allow water into and out of the cell. 3. Found in the kidneys help prevent dehydration. |
|
|
|
What is transport proteins? |
Involved in passage of molecules through the membrane. This sometimes requires input of energy. Example: sodium and potassium across a nerve cell membrane; making nerve conduction possible. |
|
|
|
What is cell recognition proteins? |
Enable our body to distinguish between our cells and cells of other organisms. These proteins are glycoproteins. |
|
|
|
What is receptor proteins? |
Allow signal molecules to bind, changing its shape and causing a cellular response. Example: insulin binds to a receptor protein on the liver cells and the liver cells stores glucose as glycogen. |
|
|
|
What are enzymatic proteins? |
Directly participate in metabolic reactions. |
|
|
|
What are junction proteins? |
Form junctions betwen cells. Cell-to-cell adhesion and communication. Keep cells together as the bladder swells with urine. |
|
|
|
All cells have: |
A plasma membrane, cytoplasm and genetic material (DNA). Plasma membrane in a cell helps to regulate movement of material. Cytoplasm in a cell is where chemical reactions occur. Genetic material (DNA) in a cell is for growth and reproduction. |
|
|
|
Main types of cells: |
Prokaryotic cells which lack a membrane-bounded nucleus. Eukaryotic cells which has a membrane-bounded nucleus. The nucleus houses DNA. |
|
|
|
Prokaryotic cells are: |
Organisms from the domain Archaea and Bacteria. Smaller and simpler in structure than eukaryotic cells. Because of their small structure they can reproduce very quickly and effectively. |
|
|
|
Bacteria is good for: |
Being decomposers. In our intestines they make vitamin 12. Used to manufacture chemicals, food, cheese, yogurt, drugs and etc. Causes diseases such TB, gonorrhea, and strep throat. |
|
|
|
Structure of a bacteria: |
Cytoplasm is surrounded by plasma membrane and cell wall. Plasma is the same in eukaryotes. Capsule is a protective layer. Cell wall maintains the shape of a cell. DNA is single circular; coiled chromosome located in nucleoid (region not membrane enclosed). Ribosomes is the site of protein synthesis (synthesis - productio of chemical compounds by reaction from simpler materials; combination or composition). |
|
|
|
Eukaryotic cells: |
Are found in protists, fungi, plants, and animals. Have a membrane-enclosed nucleus housing DNA. Much larger than prokaryotic cells. Compartmentalized and contain membraned bound organelles that carry out functions that allow the cell to be efficient and successful. |
|
|
|
What is an organells and the four types? |
Organells carry out functions that allow the cell to be efficient and successful. The four types of organelles are: 1. Nucleus and ribosomes 2. Endomembrane systems 3. Energy-related 4. Cytoskeleton |
|
|
|
What is a cytoskeleton? |
A structure that helps cells maintain their shape and internal organization, and it also provides mechanical support that enables cells to carry out essential functions like division and movement. Slides defintion- network of interconnected protein filaments and tubules (microtubules, intermediate filaments and actin filaments). Extends from the nucleus to the plasma membrane. In eukaryotes cytoskeleton maintains cell shape. |
|
|
|
The nucleus in a cell: |
Houses DNA (genetic material). Large in size. |
|
|
|
What is chromatin? |
Diffuse DNA, protein and some RNA. |
What is it made of? |
|
|
Before cell division: |
DNA compacts in chromsomes (rod like structures) all cells of an organism contain the same number of chromosomes, except the egg and sperm. DNA organized into genes, which specify a polypeptide. DNA instructions are relayed to ribosome using messenger RNA (mRNA). |
|
|
|
What is RNA? |
Ribonucleic acid (RNA) is a polymeric molecule implicated in various biological roles in coding, decoding, regulation, and expression of genes. Both RNA and DNA are nucleic acids, and along with proteins and carbohydrates, constitute the three major macromolecules essential for all known forms of life. |
|
|
|
The nucleolus: |
Is a region where ribosomal (rRNA) is made. RRNA join with proteins to form ribosomes. |
|
|
|
Nuclear envelope is: |
A double membrane phospholipid. Nuclear pores (100nm) permit passage in and out of the nucleus. (Ribosomal subunits and RNA and proteins). |
|
|
|
Functions of ribosomes: |
Carry out protein synthesis in the cytoplasm. Found in both prokaryotes and eukaryotes. Composed of 2 units, a small and large one. Each has it owns mix of proteins and ribosomal (rRNA). Receives rRNA as instructions sequence of amino acids in a polypeptide. In eukaryotes: some ribosomes are free in cytoplasm and many attached to endoplasmic reticulum. |
|
|
|
What is polypeptide? |
Are chains of amino acids. Proteins are made up of one or more polypeptides molecules. They are covalent bonds. |
|
|
|
What is the endomembrane system? |
Consists of nuclear envelope, membranes of endoplasmic reticulum, golgi appartus and numerous vesicles. The system helps to compartmentalize cell and restricts certain reactions to specific regions. The transport vesicles carry molecules from one part of the system to another. |
|
|
|
What is endoplasmic reticulum (ER)? |
A complicated system of membrane channels and saccules (flatten vesicles). Physically continous with outer membrane of nuclear envelope. |
|
|
|
Rough endoplasmic reticulum: |
Studded with ribosomes on the side that face the cytoplasm. Where polypeptide synthesis occurs. Rough ER is where proteins are modified in the lumen. (Lumen-the inside space of a cellular component or structure). |
|
|
|
Smooth endoplasmic reticulum: |
Continous with rough endoplasmic reticulum (ER). No ribsomoes attached (why its smooth). Synthesizes lipids like phosopholipids and steroids. Function depends on the cell type ( produces testosterone in the testes, detoxifies drugs in the liver and produces transport vesicles). |
|
|
|
What is the golgi appartus? |
A stack of flattened saccules (vesicles). Transfer station. Receives vesicles from endoplasmic reticulum (ER). Sorts and repackes for new destination ( to stay within the cell or be secreted; some are lysosomes). |
|
|
|
What is lysosomes? |
Vesicles that digest molecules or portions of the cell. Produced by the golgi appartus. Are digestive enzymes. Do not have membranes.
Tay-sachs disease- a genetic disorger where lysosomes in the nerve cells are missing an enzyme to degrade it and leads to a build up of lipids and impaired cell functions. Gene therapy might be able to replace missing enzyme. |
|
|
|
Vacuoles are: |
Membrane sacs similar to vesicle. Larger than vesicle. Rid cell of excess water. Helps aid in digestion of nutrients. Helps with storage: In animals: adipocytes (fat cells) contain large amount of lipid-engorged vacuoles. In plants: pigments, sugar, salts, and toxic substances Stores substances such as ions or nutrients. |
|
|
|
Energy-related organelles: |
Chloroplasts and mitochondria. |
|
|
|
Chloroplasts functions: |
Use in solar energy carbon dioxide and water to synthesize carbohydrates through the process of photosynthesis. Found in plants and algae. It is a 3 membrane system: double membrane enclosing inner space called STROMA. Thylakoids within the stroma are formed from a 3rd membrane. Thylakoid membrane contains pigments that capture solar energy. Chloroplasts have their own DNA and ribosomes. |
|
|
|
Mitochondria are: |
Found in both plants and animals. Only visible under an electron microscope. Bounded by double membrane (inner and outer membrane). Break down carbohydrates to produce ATP (adenosine triphosphate) which are the powerhouse of the cell. Where cellular respiration takes place. Cellular respiration is the complete breakdown of carbohydrates needs oxygen, produces carbon dioxide. Inner membrane called cristae. The cristae increases surface area. Inner membrane encloses matrix. Contains a concentrated mixture of enzymes assisting in carbohydrates breakdown. The reactions permit ATP enzymes to take place on the cristae. |
|
|
|
What are motor proteins? |
Allow cell and organelles to move. Instrumental in allowing cellular movements. Types of motor proteins: myosin, kinesin, and dynein. |
|
|
|
Mysoin is a motor protein: |
That interacts with actin filaments. Cells move in amoeboid fashion. Muscle contraction. |
|
|
|
Kinesin and dynein are motor proteins: |
Move along the microtubules. Transport vesicles from golgi appartus to their final destination. |
|
|
|
What are microtubules? |
Small, hollow cylinders. Assembled by centrosomes. Help maintain cell shape and act as the track for organelles and other materials to move. |
|
|
|
Intermediate filaments are: |
Intermediate in size. Ropelike assembly. Run from the nucleus envelope to plasma membrane giving support to both. |
|
|
|
What are actin filaments? |
2 chain of monomers twisted in a helix. Forms a dense web to support the cell, which gives it shape and shape microvilli. |
|
|
|
What are centrioles? |
Short barrel shaped organelles, made of 9 sets of microtubules triplets. Two centrioles lie at right angles. Found in animal cells, not present in plant cells. |
|
|
|
Cilia and flagella: |
Found in eukaryotes. Used for movement of the cells or fluid past the cell. Both have a 9+2 pattern of microtubules. Ciliar is shorter and more numerous than flagella. Cilia is 2-10 um. Cilia movement is stiff. Example: it is used in the respiratory tract or in moving the egg along the oviduct where it can be fertilized by the sperm. Flagella move in an undulating snake like manner. Flagella is 200 um. |
|
|
|
Plant cells walls: |
The primary cell wall is made of cellulose fibrils and noncellulose substances. Wall stretches when cell is growing. Found in all plant cells Secondary cell wall (found in some plant cells) forms inside primary cell wall and contains more cellulose fibril. The substance lignin adds strength. |
|
|
|
What is plasmodesmata? |
Plant cells are connected by numerous membrane lined channels that pass through cell walls. Allow the direct exchange of water and small solutes between cells.. Small solutes are sugars, water, and salt. |
|
|
|
Exterior cell surfaces in animals: |
Do not have a cell wall but an extracellular matrix (ECM). An extracellular matrix is a meshwork of fibrous proteins and polysaccharides in assoication with the cell that produce them. Collagen and elastin are well-known proteins. Collagens resist stretching and elastin gives its resilience. The matrix varies in flexibility. In cartilage it is flexible and in bone it is hard. Other proteins that permit communication between the extracellular matrix and the cytoskeleton. |
|
|
|
The three types of junctions between cells: |
Adhesion, tight and gap junctions. |
|
|
|
Adhesion junction is: |
An internal cytoplasmic plaques, attached to the cytoskeleton, and are joined by intercellular filaments. Holds cells together. Results in a sturdy but flexible sheets of cells. |
|
|
|
A tight junction is: |
Where plasma membrane proteins attach to each other. Produces a zipper-like fastening. Found where cells of tissues serve as barriers. Example: urine stays in the kidney tubules. |
|
|
|
A gap junctions is: |
Where cells are allowed to communicate through plasma membrane channels. Formed when two identical plasma membranes channels join. Channel of each cell is lined with 6 plasma membrane protein, that allow the junction to open and close. Lend strength while allowing small molecules and ions to pass through. (Example: important in heart muscle and smooth muscle). |
|
